third_party/ulib/musl/src/stdio/fgetln.c

#define _GNU_SOURCE
#include "stdio_impl.h"
#include <string.h>

char* fgetln(FILE* f, size_t* plen) {
    char *ret = 0, *z;
    ssize_t l;
    FLOCK(f);
    ungetc(getc_unlocked(f), f);
    if ((z = memchr(f->rpos, '\n', f->rend - f->rpos))) {
        ret = (char*)f->rpos;
        *plen = ++z - ret;
        f->rpos = (void*)z;
    } else if ((l = getline(&f->getln_buf, (size_t[]){}, f)) > 0) {
        *plen = l;
        ret = f->getln_buf;
    }
    FUNLOCK(f);
    return ret;
}