Building ik_llama.cpp on modern Fedora, glibc, GCC & CUDA versions #1111

sammcj · 2026-01-06T11:35:10Z

sammcj
Jan 6, 2026

I went down a bit of a rabbit hole trying to get ik_llama.cpp properly configuring and compiling on my machine so I thought I'd document it here in case anyone else has similar issues.

Fedora 43
GCC 15.2.1
GLIBC 2.42-5
CUDA 12.9

Problem 1: Math Function Exception Specification Mismatch

Error Message

/usr/include/bits/mathcalls.h(83): error: exception specification is
incompatible with that of previous function "cospi" (declared at line 2601
of /usr/local/cuda/bin/../targets/x86_64-linux/include/crt/math_functions.h)

   extern double cospi (double __x) noexcept (true); extern double __cospi (double __x) noexcept (true);
                                    ^

/usr/include/bits/mathcalls.h(85): error: exception specification is
incompatible with that of previous function "sinpi"
...
/usr/include/bits/mathcalls.h(206): error: exception specification is
incompatible with that of previous function "rsqrt"
...
6 errors detected in the compilation of "CMakeCUDACompilerId.cu".

Cause

glibc 2.41+ added C23 math functions (sinpi, cospi, rsqrt, etc.) with noexcept(true)
specifications. CUDA's headers declare these same functions without the exception
specification, causing a conflict.

Fix

Patch two CUDA header files to add exception specifications:

File 1: /usr/local/cuda/targets/x86_64-linux/include/crt/math_functions.h

Backup first:

sudo cp /usr/local/cuda/targets/x86_64-linux/include/crt/math_functions.h \
        /usr/local/cuda/targets/x86_64-linux/include/crt/math_functions.h.backup

Apply these changes (line numbers are approximate):

Line ~597:
- extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 rsqrt(double x);
+ extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 rsqrt(double x) noexcept (true);

Line ~621:
- extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  rsqrtf(float x);
+ extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  rsqrtf(float x) noexcept (true);

Line ~2556:
- extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 sinpi(double x);
+ extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 sinpi(double x) noexcept (true);

Line ~2579:
- extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  sinpif(float x);
+ extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  sinpif(float x) noexcept (true);

Line ~2601:
- extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 cospi(double x);
+ extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 cospi(double x) noexcept (true);

Line ~2623:
- extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  cospif(float x);
+ extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  cospif(float x) noexcept (true);

Or use sed:

CUDA_MATH_H="/usr/local/cuda/targets/x86_64-linux/include/crt/math_functions.h"

sudo sed -i 's/^extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 rsqrt(double x);$/extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 rsqrt(double x) noexcept (true);/' "$CUDA_MATH_H"
sudo sed -i 's/^extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  rsqrtf(float x);$/extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  rsqrtf(float x) noexcept (true);/' "$CUDA_MATH_H"
sudo sed -i 's/^extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 sinpi(double x);$/extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 sinpi(double x) noexcept (true);/' "$CUDA_MATH_H"
sudo sed -i 's/^extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  sinpif(float x);$/extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  sinpif(float x) noexcept (true);/' "$CUDA_MATH_H"
sudo sed -i 's/^extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 cospi(double x);$/extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 cospi(double x) noexcept (true);/' "$CUDA_MATH_H"
sudo sed -i 's/^extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  cospif(float x);$/extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  cospif(float x) noexcept (true);/' "$CUDA_MATH_H"

File 2: /usr/local/cuda/targets/x86_64-linux/include/crt/math_functions.hpp

Backup first:

sudo cp /usr/local/cuda/targets/x86_64-linux/include/crt/math_functions.hpp \
        /usr/local/cuda/targets/x86_64-linux/include/crt/math_functions.hpp.backup

Apply these changes:

Line ~2982:
- __func__(double sinpi(double a))
+ __func__(double sinpi(double a)) throw()

Line ~3012:
- __func__(double cospi(double a))
+ __func__(double cospi(double a)) throw()

Line ~3343:
- __func__(float sinpif(const float a))
+ __func__(float sinpif(const float a)) throw()

Line ~3348:
- __func__(float cospif(const float a))
+ __func__(float cospif(const float a)) throw()

Or use sed:

CUDA_MATH_HPP="/usr/local/cuda/targets/x86_64-linux/include/crt/math_functions.hpp"

sudo sed -i 's/__func__(double sinpi(double a))$/__func__(double sinpi(double a)) throw()/' "$CUDA_MATH_HPP"
sudo sed -i 's/__func__(double cospi(double a))$/__func__(double cospi(double a)) throw()/' "$CUDA_MATH_HPP"
sudo sed -i 's/__func__(float sinpif(const float a))$/__func__(float sinpif(const float a)) throw()/' "$CUDA_MATH_HPP"
sudo sed -i 's/__func__(float cospif(const float a))$/__func__(float cospif(const float a)) throw()/' "$CUDA_MATH_HPP"

Problem 2: pthread_cond_t Initialiser Mismatch

Error Message

/usr/lib64/gcc/x86_64-redhat-linux/12/include/c++/ext/concurrence.h(252): error: too many initializer values
      __gthread_cond_t _M_cond = { { {0}, {0}, {0, 0}, {0, 0}, 0, 0, {0, 0} } };
                                                           ^

/usr/lib64/gcc/x86_64-redhat-linux/12/include/c++/bits/std_mutex.h(190): error: too many initializer values
      __gthread_cond_t _M_cond = { { {0}, {0}, {0, 0}, {0, 0}, 0, 0, {0, 0} } };
                                                                         ^

4 errors detected in the compilation of "*.cu".

Cause

The CUDA-specific GCC 12 installation includes its own copy of pthread.h at:
/usr/lib64/gcc/x86_64-redhat-linux/12/include/pthread.h

This file contains an outdated PTHREAD_COND_INITIALIZER macro from an older glibc
that doesn't match the glibc 2.42 pthread_cond_t structure.

Old (wrong):

#define PTHREAD_COND_INITIALIZER { { {0}, {0}, {0, 0}, {0, 0}, 0, 0, {0, 0} } }

New (correct for glibc 2.42):

#define PTHREAD_COND_INITIALIZER { { {0}, {0}, {0, 0}, 0, 0, {0, 0}, 0, 0 } }

Fix

Update the PTHREAD_COND_INITIALIZER in the GCC 12 pthread.h header:

OLD_PTHREAD="/usr/lib64/gcc/x86_64-redhat-linux/12/include/pthread.h"

# Backup
sudo cp "$OLD_PTHREAD" "${OLD_PTHREAD}.backup"

# Fix the PTHREAD_COND_INITIALIZER
sudo sed -i 's/#define PTHREAD_COND_INITIALIZER { { {0}, {0}, {0, 0}, {0, 0}, 0, 0, {0, 0} } }/#define PTHREAD_COND_INITIALIZER { { {0}, {0}, {0, 0}, 0, 0, {0, 0}, 0, 0 } }/' "$OLD_PTHREAD"

Verify the fix:

grep "PTHREAD_COND_INITIALIZER" "$OLD_PTHREAD"
# Should output: #define PTHREAD_COND_INITIALIZER { { {0}, {0}, {0, 0}, 0, 0, {0, 0}, 0, 0 } }

Script

This script (or something like it) should work:

#!/bin/bash
# fix-cuda-glibc242.sh
# Fix CUDA 12.x + glibc 2.42 compatibility issues
# Tested on Fedora 43 with CUDA 12.9 and glibc 2.42
#
# This script fixes two issues:
# 1. Math function exception specification mismatch (cospi, sinpi, rsqrt, etc.)
# 2. pthread_cond_t initialiser mismatch in CUDA's bundled GCC headers

set -e

RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m'

echo -e "${GREEN}CUDA + glibc 2.42 Compatibility Fix${NC}"
echo "===================================="

# Detect CUDA path
CUDA_PATH="${CUDA_PATH:-/usr/local/cuda}"
if [ ! -d "$CUDA_PATH" ]; then
    echo -e "${RED}Error: CUDA not found at $CUDA_PATH${NC}"
    echo "Set CUDA_PATH environment variable if installed elsewhere"
    exit 1
fi

CUDA_MATH_H="$CUDA_PATH/targets/x86_64-linux/include/crt/math_functions.h"
CUDA_MATH_HPP="$CUDA_PATH/targets/x86_64-linux/include/crt/math_functions.hpp"
GCC12_PTHREAD="/usr/lib64/gcc/x86_64-redhat-linux/12/include/pthread.h"

# Check if running as root for system files
check_perms() {
    if [ ! -w "$1" ]; then
        echo -e "${YELLOW}Note: You may need sudo to modify $1${NC}"
        return 1
    fi
    return 0
}

# Fix 1: CUDA math_functions.h
if [ -f "$CUDA_MATH_H" ]; then
    echo -e "\n${GREEN}[1/3] Patching math_functions.h${NC}"

    if grep -q "rsqrt(double x) noexcept" "$CUDA_MATH_H"; then
        echo "  Already patched, skipping"
    else
        cp "$CUDA_MATH_H" "${CUDA_MATH_H}.backup" 2>/dev/null || sudo cp "$CUDA_MATH_H" "${CUDA_MATH_H}.backup"

        sed_cmd="sed -i"
        check_perms "$CUDA_MATH_H" || sed_cmd="sudo sed -i"

        $sed_cmd 's/^extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 rsqrt(double x);$/extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 rsqrt(double x) noexcept (true);/' "$CUDA_MATH_H"
        $sed_cmd 's/^extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  rsqrtf(float x);$/extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  rsqrtf(float x) noexcept (true);/' "$CUDA_MATH_H"
        $sed_cmd 's/^extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 sinpi(double x);$/extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 sinpi(double x) noexcept (true);/' "$CUDA_MATH_H"
        $sed_cmd 's/^extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  sinpif(float x);$/extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  sinpif(float x) noexcept (true);/' "$CUDA_MATH_H"
        $sed_cmd 's/^extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 cospi(double x);$/extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ double                 cospi(double x) noexcept (true);/' "$CUDA_MATH_H"
        $sed_cmd 's/^extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  cospif(float x);$/extern __DEVICE_FUNCTIONS_DECL__ __device_builtin__ float                  cospif(float x) noexcept (true);/' "$CUDA_MATH_H"

        echo "  Patched (backup: ${CUDA_MATH_H}.backup)"
    fi
else
    echo -e "${YELLOW}[1/3] Skipping math_functions.h (not found)${NC}"
fi

# Fix 2: CUDA math_functions.hpp
if [ -f "$CUDA_MATH_HPP" ]; then
    echo -e "\n${GREEN}[2/3] Patching math_functions.hpp${NC}"

    if grep -q "sinpi(double a)) throw()" "$CUDA_MATH_HPP"; then
        echo "  Already patched, skipping"
    else
        cp "$CUDA_MATH_HPP" "${CUDA_MATH_HPP}.backup" 2>/dev/null || sudo cp "$CUDA_MATH_HPP" "${CUDA_MATH_HPP}.backup"

        sed_cmd="sed -i"
        check_perms "$CUDA_MATH_HPP" || sed_cmd="sudo sed -i"

        $sed_cmd 's/__func__(double sinpi(double a))$/__func__(double sinpi(double a)) throw()/' "$CUDA_MATH_HPP"
        $sed_cmd 's/__func__(double cospi(double a))$/__func__(double cospi(double a)) throw()/' "$CUDA_MATH_HPP"
        $sed_cmd 's/__func__(float sinpif(const float a))$/__func__(float sinpif(const float a)) throw()/' "$CUDA_MATH_HPP"
        $sed_cmd 's/__func__(float cospif(const float a))$/__func__(float cospif(const float a)) throw()/' "$CUDA_MATH_HPP"

        echo "  Patched (backup: ${CUDA_MATH_HPP}.backup)"
    fi
else
    echo -e "${YELLOW}[2/3] Skipping math_functions.hpp (not found)${NC}"
fi

# Fix 3: GCC 12 pthread.h (if present)
if [ -f "$GCC12_PTHREAD" ]; then
    echo -e "\n${GREEN}[3/3] Patching GCC 12 pthread.h${NC}"

    if grep -q "PTHREAD_COND_INITIALIZER { { {0}, {0}, {0, 0}, 0, 0" "$GCC12_PTHREAD"; then
        echo "  Already patched, skipping"
    else
        cp "$GCC12_PTHREAD" "${GCC12_PTHREAD}.backup" 2>/dev/null || sudo cp "$GCC12_PTHREAD" "${GCC12_PTHREAD}.backup"

        sed_cmd="sed -i"
        check_perms "$GCC12_PTHREAD" || sed_cmd="sudo sed -i"

        $sed_cmd 's/#define PTHREAD_COND_INITIALIZER { { {0}, {0}, {0, 0}, {0, 0}, 0, 0, {0, 0} } }/#define PTHREAD_COND_INITIALIZER { { {0}, {0}, {0, 0}, 0, 0, {0, 0}, 0, 0 } }/' "$GCC12_PTHREAD"

        echo "  Patched (backup: ${GCC12_PTHREAD}.backup)"
    fi
else
    echo -e "${YELLOW}[3/3] Skipping GCC 12 pthread.h (not found)${NC}"
fi

echo -e "\n${GREEN}Done!${NC}"
echo "You can now run cmake and build your CUDA project."
echo ""
echo "To restore original files, use the .backup files created."

References

Notes

These fixes modify system CUDA headers and may need to be reapplied after CUDA updates
The pthread.h fix may vary depending on your specific GCC/CUDA installation paths
Tested with ik_llama.cpp on Fedora 43 with CUDA 12.9 and glibc 2.42

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Building ik_llama.cpp on modern Fedora, glibc, GCC & CUDA versions #1111

Uh oh!

{{title}}

Uh oh!

Uh oh!

{{editor}}'s edit

{{editor}}'s edit

Uh oh!

Replies: 0 comments

Select a reply

Uh oh!

Building ik_llama.cpp on modern Fedora, glibc, GCC & CUDA versions #1111

Uh oh!

Uh oh!

sammcj Jan 6, 2026

Problem 1: Math Function Exception Specification Mismatch

Error Message

Cause

Fix

File 1: /usr/local/cuda/targets/x86_64-linux/include/crt/math_functions.h

File 2: /usr/local/cuda/targets/x86_64-linux/include/crt/math_functions.hpp

Problem 2: pthread_cond_t Initialiser Mismatch

Error Message

Cause

Fix

Script

References

Notes

Replies: 0 comments

sammcj
Jan 6, 2026