为什么当我使用makefile编译程序时，我得到了：
gcc -Wall -pedantic src/main.c -o _wk/main.o
src/main.c:9:11: warning: C++ style comments are not allowed in ISO C90
src/main.c:9:11: warning: (this will be reported only once per input file)
src/main.c: In function ‘initialiseStructItimerval’:
src/main.c:46: warning: format ‘%d’ expects type ‘int’, but argument 2 has type ‘__suseconds_t’
src/main.c: In function ‘stockeRetard’:
src/main.c:71: warning: ISO C90 forbids mixed declarations and code
src/main.c: In function ‘main’:
src/main.c:141: warning: ISO C90 forbids mixed declarations and code
src/main.c:139: warning: unused variable ‘i’
Debut de l'edition des liens...
cd _wk ; gcc -o ../test main.o
main.o: In function `_start':
(.text+0x0): multiple definition of `_start'
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 0 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 1 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 2 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 3 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 4 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 5 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 6 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 7 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 8 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 9 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 10 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 11 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 12 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 13 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 14 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 15 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 16 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 17 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 18 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 19 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 20 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 21 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 22 has invalid symbol index 22
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_line): relocation 0 has invalid symbol index 2
/usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../lib/crt1.o:/build/buildd/eglibc-2.11.1/csu/../sysdeps/i386/elf/start.S:119: first defined here
main.o:(.rodata+0x0): multiple definition of `_fp_hw'
/usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../lib/crt1.o:(.rodata+0x0): first defined here
main.o: In function `_fini':
(.fini+0x0): multiple definition of `_fini'
/usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../lib/crti.o:(.fini+0x0): first defined here
main.o:(.rodata+0x4): multiple definition of `_IO_stdin_used'
/usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../lib/crt1.o:(.rodata.cst4+0x0): first defined here
main.o: In function `__data_start':
(.data+0x0): multiple definition of `__data_start'
/usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../lib/crt1.o:(.data+0x0): first defined here
main.o: In function `__data_start':
(.data+0x4): multiple definition of `__dso_handle'
/usr/lib/gcc/i486-linux-gnu/4.4.3/crtbegin.o:(.data+0x0): first defined here
main.o: In function `_init':
(.init+0x0): multiple definition of `_init'
/usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../lib/crti.o:(.init+0x0): first defined here
/usr/lib/gcc/i486-linux-gnu/4.4.3/crtend.o:(.dtors+0x0): multiple definition of `__DTOR_END__'
main.o:(.dtors+0x4): first defined here
collect2: ld returned 1 exit status
make: *** [all] Erreur 1
我的makefile是这样的：
CC=gcc
LD=gcc
C_FLAGS= -Wall -pedantic
#Dossier de workarea pour la generation
RWK=_wk
#Liste des dossier dans lesquels effectuer la recherche ordonnee
DIRS= \
src \
bin \
$(RWK)
#Definition de la liste des sources C a compiler
SRC_C=$(shell (for src in $$(find . -type f -name *.c) ; do basename $$src ; done))
#Liste des fichiers objets
C_OBJS=$(SRC_C:.c=.o)
vpath %.c $(DIRS)
#Regle principale
all: init_wk $(C_OBJS)
@echo "Debut de l'edition des liens..."
cd $(RWK) ; $(LD) -o test $(C_OBJS)
@echo "Compilation terminee."
#Regle de generation des fichier c->o
%.o : %.c
@echo "Compilation des .c : $<"
$(CC) $(C_FLAGS) $< -o $(RWK)/$@
#Regle a appeler pour le nettoyage de RWK
clean:
@echo "Nettoyage du dossier de travail"
@if [ -d $(RWK) ] ; then rm -rf $(RWK) ; fi
#Regle d'initialisation de la workarea
init_wk: clean
@echo "Creation du dossier de travail..."
@mkdir $(RWK)
@if [ -e ./out ]; then echo "Existe deja"; else mkdir ./out; fi
但是，当我尝试使用这样的简单makefile并且没有包含文件夹时，我没有错误：
CC=gcc
LD=gcc
BIN = hello
SRCS=$(wildcard *.c)
OBJS = $(SRCS:.c=.o)
DEPS = $(SRCS:.c=.d)
CFLAGS = -W -Wall -pedantic
all: $(BIN)
$(BIN): $(OBJS)
$(LD) -o $@ $(OBJS)
%.o: %.c
$(CC) -o $@ -c $< $(CFLAGS)
%.d: %.c
$(CC) $(CFLAGS) -MM -MD -o $@ $<
-include $(DEPS)
.PHONY: clean distclean
clean:
rm -rf $(OBJS)
很抱歉这篇长篇文章，但我不明白我的错误：/
答案 0 :(得分：18)
仅编译单个模块（不链接它们）时，添加-c作为编译器参数，以防止它每次链接c / c ++运行时。
如果您想获取可执行文件或库文件，请不要添加-c。如果您想获取.o文件，请添加-c。
答案 1 :(得分：8)
%.o : %.c
@echo "Compilation des .c : $<"
$(CC) $(C_FLAGS) $< -o $(RWK)/$@
这里有一个问题：没有-c选项，gcc将编译并链接。试试这个：
$(CC) $(C_FLAGS) -c $< -o $(RWK)/$@
此外，$(CFLAGS)比$(C_FLAGS)
答案 2 :(得分：3)
我遇到了同样的问题。我不小心删掉了我的主要功能。你可能会检查你的是否还在那里。