Cygwin C program not accepting command line arguments

Question

I am writing a program in C that uses SDL2 on Cygwin. The problem I am having is that argc is always 1, even when the command line does contain other arguments.

This is a bit difficult to replicate as I can't post all the code for this program, but I can include the main source here to make sure my main function is correct.

My question is if there is any known reason why argc would always be 1 and not include other command line arguments (weather this be intentionally or a side effect from using SDL2 etc)?

This is the code i'm using:

#include <stdlib.h>
#include <stdio.h>
#include "config.h"
#include <string.h>

#ifdef SIGNAL_AVAIL
#include <signal.h>
#endif

#include "process.h"
#include "nvconsole.h"
#include "stringutils.h"

#include "nova.h"

struct NovaContext_s *context;      // Nova system context

#ifdef SIGNAL_AVAIL

// #### Signal Handler ####
void sig_handler(int signo)
{
    if (signo == SIGINT)
    {   
        NVConsole_print(NVInfo,"Terminated by user");       
        NVConsole_println(NVInfo,"");
        Nova_cleanUp(context);      
        exit(0);
    }   
}

#endif

void init()
{
#ifdef SIGNAL_AVAIL
    if (signal(SIGINT, sig_handler) == SIG_ERR)
    {
        NVConsole_println(NVError,"[main] Can't catch SIGINT");
        exit(1);
    }   
    if (signal(SIGQUIT, sig_handler) == SIG_ERR)
    {
        NVConsole_println(NVError,"[main] Can't catch SIGQUIT");
        exit(1);
    }
#endif
}

int main(int argc, char* argv[]) {

for(int i=0;i<argc;i++) printf("%d %s\n",i,argv[i]);

    init();

    context = Nova_createContext();

    Nova_init(context); 
    Nova_loop(context,0);
    Nova_cleanUp(context);

    return 0;
}

Although this code doesn't directly use SDL, it is being linked and is used by other parts of the included code. I get the below output from this:

$ ./bin/nova
0 F:\dev\nova\bin\nova.exe

$ ./bin/nova hello
0 F:\dev\nova\bin\nova.exe

I've included the makefile below:

ARCH = $(shell uname)

CXX=gcc -std=c99 

ifeq ($(ARCH), Darwin)
    SDLFLAGS = `/usr/local/bin/sdl2-config --cflags`
    SDLLIBS = `/usr/local/bin/sdl2-config --libs`
else
    SDLFLAGS = `sdl2-config --cflags`
    SDLLIBS = `sdl2-config --libs`
endif

#OPT= -O2 -s -D_GNU_SOURCE
OPT= -O2 -D_GNU_SOURCE

INCLUDE=-I. -I.. -Isrc/nova -Isrc/nvscript -Isrc/common -Isrc/headers -Isrc/modules -Isrc/search

#WARN=-Werror
CWD=$(shell pwd)

#CXXFLAGS= $(OPT) $(INCLUDE) $(SDLFLAGS) $(WARN) -fPIC
CXXFLAGS= $(OPT) $(INCLUDE) $(SDLFLAGS) $(WARN)

LIBS= -lm $(SDLLIBS) -ldl

LD=$(CXX) $(OPT)

#####################################################

LIBNVSCRIPT_API_VERSION = 1.0.0

#####################################################

COMP   = nova \
         nvdata \
         nvconsole \
         nvdatastore \
         nvconfig \
         nvevent \
         rule_clock \
         rule_nvs
COMP_H = nova.h \
         nvdata.h \
         nvconsole.h \
         nvdatastore.h \
         nvconfig.h \
         nvevent.h \
         rule_clock.h \
         rule_nvs.h
COMP_HEADERS := $(addprefix src/nova/, $(COMP_H) )
COMP_OBJS    := $(addprefix objs/, $(COMP:=.o) )
COMP_LIB     := libs/libnova.a

#####################################################

NVSCRIPT   = nvscript \
             nvscriptcore \
             nvscriptresult \
             nvscriptlist \
             nvscriptstring \
             nvscriptfile \
             nvscriptnet \
             nvscriptprocess \
             nvscriptdebug \
             nvscriptexec \
             nvscriptmath
NVSCRIPT_H = nvscript.h \
             nvscriptcore.h \
             nvscriptresult.h \
             nvscriptlist.h \
             nvscriptstring.h \
             nvscriptfile.h \
             nvscriptnet.h \
             nvscriptprocess.h \
             nvscriptdebug.h \
             nvscriptexec.h \
             nvscriptmath.h
NVSCRIPT_HEADERS := $(addprefix src/nvscript/, $(NVSCRIPT_H) )
NVSCRIPT_OBJS    := $(addprefix objs/, $(NVSCRIPT:=.o) )
NVSCRIPT_LIB     := libs/libnvscript-$(LIBNVSCRIPT_API_VERSION).a

#####################################################

COMMON   = stringutils \
           fileutils \
           wildcard \
           intarray \
           floatarray \
           chararray \
           stringarray \
           uchararray \
           boolarray \
           voidarray \
           base64 \
           sha1 \
           scramble \
           lfp \
           x86_intmem \
           x86_console \
           x86_file \
           x86_timer \
           x86_net \
           x86_process \
           x86_rtc \
           x86_keys \
           sdl_video \
           sdl_input
COMMON_H = stringutils.h \
           fileutils.h \
           mallocdebug.h \
           wildcard.h \
           intarray.h \
           floatarray.h \
           chararray.h \
           stringarray.h \
           uchararray.h \
           boolarray.h \
           base64.h \
           voidarray.h \
           sha1.h \
           scramble.h \
           lfp.h \
           x86_intmem.h \
           x86_console.h \
           x86_file.h \
           x86_timer.h \
           x86_net.h \
           x86_process.h \
           x86_rtc.h \
           x86_keys.h \
           sdl_video.h \
           sdl_input.h
COMMON_HEADERS := $(addprefix src/common/, $(COMMON_H) )
COMMON_OBJS    := $(addprefix objs/, $(COMMON:=.o) )
COMMON_LIB     := libs/libmlcommon.a

#####################################################

SEARCH = search searchitem
SEARCH_H = search.h searchitem.h
SEARCH_HEADERS := $(addprefix src/search/, $(SEARCH_H) )
SEARCH_OBJS    := $(addprefix objs/search/, $(SEARCH:=.o) )
SEARCH_LIB     := libs/libsearch.a

#####################################################

MODULES   = ui statusbar welcome context netmsg
MODULES_H = ui.h statusbar.h welcome.h context.h netmsg.h
MODULES_HEADERS := $(addprefix src/modules/, $(MODULES_H) )
MODULES_OBJS    := $(addprefix objs/modules/, $(MODULES:=.o) )
MODULES_DSOS    := $(addprefix modules/, $(MODULES:=.so) )

#####################################################

OUTPUT = main
OUTPUT_OBJS  := $(addprefix objs/, $(OUTPUT:=.o) )
OUTPUT_BINARY = bin/nova

NVSOUTPUT = nvs
NVSOUTPUT_OBJS  := $(addprefix objs/, $(NVSOUTPUT:=.o) )
NVSOUTPUT_BINARY = bin/nvs

NVSTESTOUTPUT = nvstest
NVSTESTOUTPUT_OBJS  := $(addprefix objs/, $(NVSTESTOUTPUT:=.o) )
NVSTESTOUTPUT_BINARY = bin/nvstest

SEARCHOUTPUT = search
SEARCHOUTPUT_OBJS  := $(addprefix objs/, $(SEARCHOUTPUT:=.o) )
SEARCHOUTPUT_BINARY = bin/search

#####################################################

default: $(COMP_LIB) $(NVSCRIPT_LIB) $(COMMON_LIB) $(SEARCH_LIB) $(OUTPUT_BINARY) $(NVSOUTPUT_BINARY) $(NVSTESTOUTPUT_BINARY) $(SEARCHOUTPUT_BINARY)
modules: $(MODULES_OBJS) $(MODULES_DSOS)
nova: $(COMP_LIB) $(NVSCRIPT_LIB) $(COMMON_LIB) $(OUTPUT_BINARY)
nvs: $(NVSCRIPT_LIB) $(COMMON_LIB) $(NVSOUTPUT_BINARY) $(NVSTESTOUTPUT_BINARY)

#################### Components #####################

objs/%.o: src/nova/%.c $(COMP_HEADERS)
    @echo "Compiling $<"
    @$(CXX) $(CXXFLAGS) -o $@ -c $<

$(COMP_LIB): $(COMP_OBJS)
    @echo "Building the nova library ($(COMP_LIB))"
    @ar rcs $(COMP_LIB) $(COMP_OBJS)

##################### NVScript ######################

objs/%.o: src/nvscript/%.c $(NVSCRIPT_HEADERS)
    @echo "Compiling $<"
    @$(CXX) $(CXXFLAGS) -o $@ -c $<

$(NVSCRIPT_LIB): $(NVSCRIPT_OBJS)
    @echo "Building the nvscript library ($(NVSCRIPT_LIB))"
    @ar rcs $(NVSCRIPT_LIB) $(NVSCRIPT_OBJS)

#################### Common #####################

objs/%.o: src/common/%.c $(COMMON_HEADERS)
    @echo "Compiling $<"
    @$(CXX) $(CXXFLAGS) -o $@ -c $<

$(COMMON_LIB): $(COMMON_OBJS)
    @echo "Building the mlcommon library ($(COMMON_LIB))"
    @ar rcs $(COMMON_LIB) $(COMMON_OBJS)

################## MODULES #####################

# Compile plugin and then link to shared library

objs/modules/%.o: src/modules/%.c $(MODULES_HEADERS)
    @echo "Compiling module \"$*\""
    @$(CXX) $(CXXFLAGS) -o $@ -c $<

modules/%.so: objs/modules/%.o $(MODULES_HEADERS)
    @echo "Linking module \"$*\""   
    @$(CXX) -shared -o $@  $(COMP_OBJS) $(NVSCRIPT_OBJS) $(COMMON_OBJS) $(LIBS) $<

#################### Search #####################

objs/search/%.o: src/search/%.c $(SEARCH_HEADERS)
    @echo "Compiling $<"
    @$(CXX) $(CXXFLAGS) -o $@ -c $<

$(SEARCH_LIB): $(SEARCH_OBJS)
    @echo "Building the search library ($(SEARCH_LIB))"
    @ar rcs $(SEARCH_LIB) $(SEARCH_OBJS)

###################### Output #######################

objs/main.o: src/main/nova.c $(COMP_HEADERS) $(NVSCRIPT_HEADERS) $(COMMON_HEADERS)
    @echo "Building binary ($<)"    
    @$(CXX) $(CXXFLAGS) -o $@ -c $<

objs/nvs.o: src/main/nvs.c $(NVSCRIPT_HEADERS) $(COMMON_HEADERS)
    @echo "Building binary ($<)"
    @$(CXX) $(CXXFLAGS) -o $@ -c $<

objs/nvstest.o: src/main/nvstest.c $(NVSCRIPT_HEADERS) $(COMMON_HEADERS)
    @echo "Building binary ($<)"
    @$(CXX) $(CXXFLAGS) -o $@ -c $<

objs/search.o: src/main/search.c $(SEARCH_HEADERS) $(COMMON_HEADERS)
    @echo "Building binary ($<)"
    @$(CXX) $(CXXFLAGS) -o $@ -c $<


$(OUTPUT_BINARY): $(OUTPUT_OBJS) $(COMP_LIB) $(NVSCRIPT_LIB) $(COMMON_LIB)
    @echo "Linking $@"
    @$(CXX) -o $@ $(OUTPUT_OBJS) $(COMP_OBJS) $(NVSCRIPT_OBJS) $(COMMON_OBJS) $(LIBS)

$(NVSOUTPUT_BINARY): $(NVSOUTPUT_OBJS) $(NVSCRIPT_LIB) $(COMMON_LIB)
    @echo "Linking $@"
    @$(CXX) -o $@ $(NVSOUTPUT_OBJS) $(NVSCRIPT_OBJS) $(COMMON_OBJS) $(LIBS)

$(NVSTESTOUTPUT_BINARY): $(NVSTESTOUTPUT_OBJS) $(NVSCRIPT_LIB) $(COMMON_LIB)
    @echo "Linking $@"
    @$(CXX) -o $@ $(NVSTESTOUTPUT_OBJS) $(NVSCRIPT_OBJS) $(COMMON_OBJS) $(LIBS)

$(SEARCHOUTPUT_BINARY): $(SEARCHOUTPUT_OBJS) $(SEARCH_LIB) $(COMMON_LIB)
    @echo "Linking $@"
    @$(CXX) -o $@ $(SEARCHOUTPUT_OBJS) $(SEARCH_OBJS) $(COMMON_OBJS) $(LIBS)

#####################################################

install:    
    ./install.sh

uninstall:  
    ./uninstall.sh

clean:
    rm -f objs/*.o objs/modules/*.o objs/search/*.o */*.so */*.a modules/*.so libs/*.a $(OUTPUT_BINARY).exe $(OUTPUT_BINARY) $(NVSOUTPUT_BINARY).exe $(NVSOUTPUT_BINARY) $(NVSTESTOUTPUT_BINARY).exe $(NVSTESTOUTPUT_BINARY) $(SEARCHOUTPUT_BINARY) $(SEARCHOUTPUT_BINARY).exe

I've also written a small test:

#include <stdlib.h>
#include <stdio.h>

 int main(int argc, char* argv[]) {
    for(int i=0;i<argc;i++) printf("%d %s\n",i,argv[i]);
 }

And it's not surprising that this does work and displays all arguments, as you would expect.

$ ./test hello
0 ./test
1 hello

It's also worth noting that the path for argv[0] seems to be different in both examples, the first (where it's not working) shows what looks like a windows path, while the second example (which does work) is showing a linux looking path. Does this indicate anything?

Answer 1

I think argc is required here (not argv)

for(int i=0;i<argc;i++) printf("%d %s\n",i,argv[i]);