ref: 5eb2945975eab587998f04bf277ec09fcfcec0e1
dir: /lib/c/setvbuf.c/
#include <errno.h> #include <stdio.h> #include <stdlib.h> #undef setvbuf extern int _flsbuf(FILE *fp); int setvbuf(FILE * restrict fp, char * restrict buf, int mode, size_t size) { int flags, r; if (_flsbuf(fp) == EOF) return EOF; switch (mode) { case _IONBF: size = sizeof(fp->unbuf); buf = fp->unbuf; break; case _IOLBF: case _IOFBF: if (size == 0) { if ((buf = malloc(BUFSIZ)) == NULL) { errno = ENOMEM; return EOF; } size = BUFSIZ; } break; default: errno = EINVAL; return EOF; } flags = fp->flags; if (flags & _IOALLOC) free(fp->buf); flags &= ~(_IONBF | _IOLBF | _IOFBF | _IOALLOC | _IOALLOC); flags |= mode; fp->flags = flags; fp->buf = buf; fp->len = size; return 0; }