lib/cgraph: use return value of 'fread' in aglasterr

fix warning:
agerror.c: In function ‘aglasterr’:
agerror.c:49:5: warning: ignoring return value of ‘fread’, declared with attribute warn_unused_result [-Wunused-result]
   49 |     fread(buf, sizeof(char), len, agerrout);

diff --git a/lib/cgraph/agerror.c b/lib/cgraph/agerror.c
index b091ea763805edeccc376ef94ae4f76474911834..543cf7c476e0fcb6fcfbfee9908941ecaabceec0 100644 (file)
--- a/lib/cgraph/agerror.c
+++ b/lib/cgraph/agerror.c
@@ -46,7 +46,7 @@ char *aglasterr()
     size_t len = (size_t)(endpos - aglast);
     char *buf = malloc(len + 1);
     fseek(agerrout, aglast, SEEK_SET);
-    fread(buf, sizeof(char), len, agerrout);
+    len = fread(buf, sizeof(char), len, agerrout);
     buf[len] = '\0';
     fseek(agerrout, endpos, SEEK_SET);