Add child_wait() function

Can be used to wait for the termination of a child process.

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

src/calcurse.h

@@ -880,6 +880,7 @@ void         str_toupper (char *);
 void         file_close (FILE *, const char *);
 void         psleep (unsigned);
 int          fork_exec (int *, int *, const char *, char *const *);
+int          child_wait (int *, int *, int);
 
 /* vars.c */
 extern int               col, row;

src/utils.c

@@ -43,6 +43,7 @@
 #include <sys/types.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <sys/wait.h>
 
 #include "calcurse.h"
 
@@ -789,3 +790,18 @@ fork_exec (int *pfdin, int *pfdout, const char *path, char *const *arg)
     }
   return pid;
 }
+
+/* Wait for a child process to terminate. */
+int
+child_wait (int *pfdin, int *pfdout, int pid)
+{
+  int stat;
+
+  if (pfdin)
+    close (*pfdin);
+  if (pfdout)
+    close (*pfdout);
+
+  waitpid (pid, &stat, 0);
+  return stat;
+}