Build failure (Linux): implicit declaration of function

[dhdeangelis]

Currently, netcdf-c master is failing to build (Linux, see details below) with the following errors:

[ 19%] Built target h5fletcher32
In file included from /usr/local/src/netcdf-c/libdispatch/dutil.c:31:
/usr/local/src/netcdf-c/libdispatch/ncutil.h: In function ‘vlistexpand’:
/usr/local/src/netcdf-c/libdispatch/ncutil.h:70:12: warning: conversion from ‘size_t’ {aka ‘long unsigned int’} to ‘unsigned int’ may change value [-Wconversion]
   70 |   l->alloc=newsz;
      |            ^~~~~
/usr/local/src/netcdf-c/libdispatch/ncutil.h: In function ‘vsexpand’:
/usr/local/src/netcdf-c/libdispatch/ncutil.h:148:13: warning: conversion from ‘size_t’ {aka ‘long unsigned int’} to ‘unsigned int’ may change value [-Wconversion]
  148 |   vs->alloc=newsz;
      |             ^~~~~
/usr/local/src/netcdf-c/libdispatch/ncutil.h: In function ‘vsappendn’:
/usr/local/src/netcdf-c/libdispatch/ncutil.h:157:19: warning: conversion from ‘size_t’ {aka ‘long unsigned int’} to ‘unsigned int’ may change value [-Wconversion]
  157 |   if(n == 0) {n = strlen(elem);}
      |                   ^~~~~~
/usr/local/src/netcdf-c/libdispatch/dutil.c: In function ‘NC_readfile’:
/usr/local/src/netcdf-c/libdispatch/dutil.c:259:12: error: implicit declaration of function ‘NC_readfilen’; did you mean ‘NC_readfile’? [-Wimplicit-function-declaration]
  259 |     stat = NC_readfilen(filename, content, -1);
      |            ^~~~~~~~~~~~
      |            NC_readfile
In file included from /usr/local/src/netcdf-c/plugins/H5Znoop.c:8:
/usr/local/src/netcdf-c/build/include/netcdf_json.h: In function ‘NCJdictlookup’:
/usr/local/src/netcdf-c/build/include/netcdf_json.h:838:12: warning: return discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
  838 |     return jvalue;
      |            ^~~~~~
/usr/local/src/netcdf-c/libdispatch/dutil.c: In function ‘NC_readfilen’:
/usr/local/src/netcdf-c/libdispatch/dutil.c:271:11: error: implicit declaration of function ‘NC_readfileF’; did you mean ‘NC_readfilen’? [-Wimplicit-function-declaration]
  271 |     ret = NC_readfileF(stream,content,amount);
      |           ^~~~~~~~~~~~
      |           NC_readfilen
In file included from /usr/local/src/netcdf-c/build/plugins/H5Znoop1.c:9:
/usr/local/src/netcdf-c/build/include/netcdf_json.h: In function ‘NCJdictlookup’:
/usr/local/src/netcdf-c/build/include/netcdf_json.h:838:12: warning: return discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
  838 |     return jvalue;
      |            ^~~~~~
/usr/local/src/netcdf-c/libdispatch/dutil.c: In function ‘NC_getmodelist’:
/usr/local/src/netcdf-c/libdispatch/dutil.c:345:16: error: implicit declaration of function ‘NC_split_delim’ [-Wimplicit-function-declaration]
  345 |     if((stat = NC_split_delim(modestr,',',modelist))) goto done;
      |                ^~~~~~~~~~~~~~
[ 19%] Built target h5deflate
/usr/local/src/netcdf-c/libdispatch/dutil.c: In function ‘NC_testpathmode’:
/usr/local/src/netcdf-c/libdispatch/dutil.c:365:17: error: implicit declaration of function ‘NC_testmode’; did you mean ‘NC_testpathmode’? [-Wimplicit-function-declaration]
  365 |         found = NC_testmode(uri,tag);
      |                 ^~~~~~~~~~~
      |                 NC_testpathmode
/usr/local/src/netcdf-c/libdispatch/dutil.c: In function ‘NC_addmodetag’:
/usr/local/src/netcdf-c/libdispatch/dutil.c:423:14: error: implicit declaration of function ‘NC_joinwith’ [-Wimplicit-function-declaration]
  423 |     if((stat=NC_joinwith(modelist,",",NULL,NULL,&modevalue))) goto done;
      |              ^~~~~~~~~~~
/usr/local/src/netcdf-c/libdispatch/dutil.c: At top level:
/usr/local/src/netcdf-c/libdispatch/dutil.c:467:1: error: conflicting types for ‘NC_split_delim’; have ‘int(const char *, char,  NClist *)’
  467 | NC_split_delim(const char* arg, char delim, NClist* segments)
      | ^~~~~~~~~~~~~~
/usr/local/src/netcdf-c/libdispatch/dutil.c:468:1: note: an argument type that has a default promotion cannot match an empty parameter name list declaration
  468 | {
      | ^
/usr/local/src/netcdf-c/libdispatch/dutil.c:345:16: note: previous implicit declaration of ‘NC_split_delim’ with type ‘int()’
  345 |     if((stat = NC_split_delim(modestr,',',modelist))) goto done;
      |                ^~~~~~~~~~~~~~
/usr/local/src/netcdf-c/libdispatch/dutil.c: In function ‘NC_swapatomicdata’:
/usr/local/src/netcdf-c/libdispatch/dutil.c:599:17: error: implicit declaration of function ‘swapinline16’ [-Wimplicit-function-declaration]
  599 |         case 2: swapinline16(p); break;
      |                 ^~~~~~~~~~~~
[ 19%] Built target manpage
/usr/local/src/netcdf-c/libdispatch/dutil.c:600:17: error: implicit declaration of function ‘swapinline32’ [-Wimplicit-function-declaration]
  600 |         case 4: swapinline32(p); break;
      |                 ^~~~~~~~~~~~
/usr/local/src/netcdf-c/libdispatch/dutil.c:601:17: error: implicit declaration of function ‘swapinline64’ [-Wimplicit-function-declaration]
  601 |         case 8: swapinline64(p); break;
      |                 ^~~~~~~~~~~~
make[2]: *** [libdispatch/CMakeFiles/dispatch.dir/build.make:457: libdispatch/CMakeFiles/dispatch.dir/dutil.c.o] Error 1
make[2]: *** Waiting for unfinished jobs....
[ 19%] Building C object plugins/CMakeFiles/nczmisc.dir/NCZmisc.c.o
In file included from /usr/local/src/netcdf-c/libdispatch/drc.c:29:
/usr/local/src/netcdf-c/libdispatch/ncutil.h: In function ‘vlistexpand’:
/usr/local/src/netcdf-c/libdispatch/ncutil.h:70:12: warning: conversion from ‘size_t’ {aka ‘long unsigned int’} to ‘unsigned int’ may change value [-Wconversion]
   70 |   l->alloc=newsz;
      |            ^~~~~
/usr/local/src/netcdf-c/libdispatch/ncutil.h: In function ‘vsexpand’:
/usr/local/src/netcdf-c/libdispatch/ncutil.h:148:13: warning: conversion from ‘size_t’ {aka ‘long unsigned int’} to ‘unsigned int’ may change value [-Wconversion]
  148 |   vs->alloc=newsz;
      |             ^~~~~
/usr/local/src/netcdf-c/libdispatch/ncutil.h: In function ‘vsappendn’:
/usr/local/src/netcdf-c/libdispatch/ncutil.h:157:19: warning: conversion from ‘size_t’ {aka ‘long unsigned int’} to ‘unsigned int’ may change value [-Wconversion]
  157 |   if(n == 0) {n = strlen(elem);}
      |                   ^~~~~~
/usr/local/src/netcdf-c/libdispatch/drc.c: In function ‘rccompile’:
/usr/local/src/netcdf-c/libdispatch/drc.c:439:13: error: implicit declaration of function ‘NC_readfile’ [-Wimplicit-function-declaration]
  439 |     if((ret=NC_readfile(filepath,tmp))) {
      |             ^~~~~~~~~~~
/usr/local/src/netcdf-c/libdispatch/drc.c: In function ‘NC_rcfile_insert’:
/usr/local/src/netcdf-c/libdispatch/drc.c:700:21: warning: assignment discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
  700 |         entry->host = nulldup(hostport);
      |                     ^
/usr/local/src/netcdf-c/libdispatch/drc.c:702:24: warning: assignment discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
  702 |         entry->urlpath = nulldup(urlpath);
      |                        ^
make[2]: *** [libdispatch/CMakeFiles/dispatch.dir/build.make:471: libdispatch/CMakeFiles/dispatch.dir/drc.c.o] Error 1
[ 19%] Building C object plugins/CMakeFiles/h5zstd.dir/H5Zzstd.c.o
[ 19%] Building C object plugins/CMakeFiles/h5bzip2.dir/H5Zbzip2.c.o
make[1]: *** [CMakeFiles/Makefile2:2690: libdispatch/CMakeFiles/dispatch.dir/all] Error 2
make[1]: *** Waiting for unfinished jobs....
In file included from /usr/local/src/netcdf-c/plugins/NCZmisc.c:27:
/usr/local/src/netcdf-c/build/include/netcdf_json.h: In function ‘NCJdictlookup’:
/usr/local/src/netcdf-c/build/include/netcdf_json.h:838:12: warning: return discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
  838 |     return jvalue;
      |            ^~~~~~
In file included from /usr/local/src/netcdf-c/plugins/H5Zbzip2.c:36:
/usr/local/src/netcdf-c/build/include/netcdf_json.h: In function ‘NCJdictlookup’:
/usr/local/src/netcdf-c/build/include/netcdf_json.h:838:12: warning: return discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
  838 |     return jvalue;
      |            ^~~~~~
In file included from /usr/local/src/netcdf-c/plugins/H5Zzstd.c:36:
/usr/local/src/netcdf-c/build/include/netcdf_json.h: In function ‘NCJdictlookup’:
/usr/local/src/netcdf-c/build/include/netcdf_json.h:838:12: warning: return discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
  838 |     return jvalue;
      |            ^~~~~~

System
openSUSE Tumbleweed 20250822
Kernel 6.16.1
gcc 15.1.1
cmake 4.0.3

[DennisHeimbigner]

Odd. Those implicit functions appear to have signatures in netcdf-c/include/ncutil.h in main branch.
And ncutil.h appears to be included in netcdf-c/libdispatch/dutil.c.
Is that true for the version of main you have?

[dhdeangelis]

Those implicit functions appear to have signatures in netcdf-c/include/ncutil.h in main branch.
And ncutil.h appears to be included in netcdf-c/libdispatch/dutil.c.
Is that true for the version of main you have?

Yes, in my local repo:

in netcdf-c/include/ncutil.h

EXTERNL int NC__testurl(const char* path, char** basenamep);
EXTERNL int NC_isLittleEndian(void);
EXTERNL char* NC_backslashEscape(const char* s);
EXTERNL char* NC_backslashUnescape(const char* esc);
EXTERNL char* NC_entityescape(const char* s);
EXTERNL char* NC_shellUnescape(const char* esc);
EXTERNL int NC_mktmp(const char* base, char** tmpfile);
EXTERNL int NC_readfile(const char* filename, struct NCbytes* content);
EXTERNL int NC_readfilen(const char* filename, struct NCbytes* content, long long amount);
EXTERNL int NC_readfileF(FILE* stream, struct NCbytes* content, long long amount);
EXTERNL int NC_writefile(const char* filename, size_t size, void* content);
EXTERNL int NC_getmodelist(const char* modestr, struct NClist** modelistp);
EXTERNL int NC_testpathmode(const char* path, const char* tag);
EXTERNL int NC_testmode(struct NCURI* uri, const char* tag);
EXTERNL int NC_addmodetag(struct NCURI* uri, const char* tag);
EXTERNL int NC_isinf(double x);
EXTERNL int NC_isnan(double x);
EXTERNL int NC_split_delim(const char* arg, char delim, struct NClist* segments);
EXTERNL int NC_join(struct NClist* segments, char** pathp);
EXTERNL int NC_joinwith(struct NClist* segments, const char* sep, const char* prefix, const char* suffix, char** pathp);
EXTERNL void NC_sortenvv(size_t n, char** envv);
EXTERNL void NC_sortlist(struct NClist* l);
EXTERNL void NC_freeenvv(size_t nkeys, char** keys);
EXTERNL int NC_swapatomicdata(size_t datalen, void* data, int typesize);

And in netcdf-c/libdispatch/dutil.c

#include "config.h"
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef _MSC_VER
#include <io.h>
#endif
#include "netcdf.h"
#include "ncuri.h"
#include "ncbytes.h"
#include "nclist.h"
#include "nclog.h"
#include "ncrc.h"
#include "ncpathmgr.h"
#include "ncutil.h"

It apparently is also that case in the main repo.

Supposedly my local repo should be up-to-date, but I will try deleting and cloning it again just in case old stuff somehow remained.

[DennisHeimbigner]

Usually this kind of faiilure is

1. missing include
2. unclosed comment
3. #if flag that is disabled.

If #2 then you should see an error message.
If #3 then it requires more effort to find.

[dhdeangelis]

Well, I started from a fresh local clone and everything went well as usual. Build process OK. All 233 test pass OK. Do not know exactly what happened but possibly my installing script wasn't deleting the old code tree and starting with a fresh one, just updating and recompiling over the old one. Thanks for the help and sorry for the noise.

[DennisHeimbigner]

No problem.