musl/src/internal/syscall_ret.c

#include <errno.h>
#include <unistd.h>

long __syscall_ret(unsigned long r)
{
	if (r >= (unsigned long)-1 - 4096) {
		errno = -(long)r;
		return -1;
	}
	return (long)r;
}
overhaul syscall interface this commit shuffles around the location of syscall definitions so that we can make a syscall() library function with both SYS_* and __NR_* style syscall names available to user applications, provides the syscall() library function, and optimizes the code that performs the actual inline syscalls in the library itself. previously on i386 when built as PIC (shared library), syscalls were incurring bus lock (lock prefix) overhead at entry and exit, due to the way the ebx register was being loaded (xchg instruction with a memory operand). now the xchg takes place between two registers. further cleanup to arch/$(ARCH)/syscall.h is planned. 2011-03-19 18:51:42 -04:00			`#include <errno.h>`
			`#include <unistd.h>`

			`long __syscall_ret(unsigned long r)`
			`{`
			`if (r >= (unsigned long)-1 - 4096) {`
			`errno = -(long)r;`
			`return -1;`
			`}`
			`return (long)r;`
			`}`