ref: 0a5f81a44230cbd562b6d71a0a5be018e24a5ba6
dir: /sys/src/libstdio/tmpnam.c/
/* * pANS stdio -- tmpnam */ #include "iolib.h" char *tmpnam(char *s){ static char name[]="/tmp/tn000000000000"; char *p; do{ p=name+7; while(*p=='9') *p++='0'; if(*p=='\0') return NULL; ++*p; }while(access(name, 0)==0); if(s){ strcpy(s, name); return s; } return name; }