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-nostdlib

Tells the compiler to not use the Arm® standard C and C++ libraries.

If you use the -nostdlib option, armclang does not collude with the Arm standard library and only emits calls to functions that the C Standard or the AEABI defines. The output from armclang works with any ISO C library that is compliant with AEABI.

The -nostdlib armclang option, passes the --no_scanlib linker option to armlink. Therefore you must specify the location of the libraries you want to use as input objects to armlink, or with the --userlibpath armlink option.

Note

If you want to use your own libraries instead of the Arm standard libraries or if you want to re-implement the standard library functions, then you must use the -nostdlib armclang option. Your libraries must be compliant with the ISO C library and with the AEABI specification.

Default

-nostdlib is disabled by default.

Example

#include "math.h" 

double foo(double d) 
{
    return sqrt(d + 1.0);
} 
int main(int argc, char *argv[])
{
    return foo(argc);
}

Compiling this code with -nostdlib generates a call to sqrt, which is AEABI compliant.

armclang --target=arm-arm-none-eabi -mcpu=Cortex-A9 -O0 -S -o- file.c -mfloat-abi=hard -nostdlib

Compiling this code without -nostdlib generates a call to __hardfp_sqrt (from the Arm standard library), which the C Standard and the AEABI do not define.

armclang --target=arm-arm-none-eabi -mcpu=Cortex-A9 -O0 -S -o- file.c -mfloat-abi=hard
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