segment fault

/*================================================================
 *
 *tempnam() function
 *
 *
 * ================================================================*/

#include<stdio.h>

int main( int argc , char *argv[] )
{
  int n;
  if( argc!=3 ){
  printf( "usage: ./tempnam " );
  //return;
  }
  printf( "%s", tempnam( argv[1][0] != ' '?argv[1]:NULL ,argv[2][0]!=' '?argv[2]:NULL ) );
  printf( "strlen(argv1):%d\n" , strlen(argv[1]) );
  printf( "strlen(argv2):%d\n" , strlen(argv[2]) );
  //printf("%s\n", tempnam( NULL,NULL));


  return 0;
}


在执行gcc tempnam.c -o tempnam
后执行./tempnam
 就会出现segment fault !!原因是argv[1] argv[2]并没有值。



应该像这样执行才行：

$ ./a.out /home/sar TEMP specify both directory and prefix
   /home/sar/TEMPsf00zi
   $ ./a.out " " PFX use default directory: P_tmpdir
   /tmp/PFXfBw7Gi
   $ TMPDIR=/var/tmp ./a.out /usr/tmp " " use environment variable; no prefix
   /var/tmp/file8fVYNi environment variable overrides directory
   $ TMPDIR=/no/such/dir ./a.out /home/sar/tmp QQQ
   /home/sar/tmp/QQQ98s8Ui invalid environment dire