GCC makefile不接受-std = c99 -lm

Question

I am having problem with my makefile with gcc compiler. If I use gcc directly as:

gcc -std=c99 -lm tm.c tm_coins.c tm_options.c tm_stock.c tm_utility.c -o tm -Wall -pedantic

Everything works fine. I need -std-c99 and -lm.

However, I have been told to use makefile. Here is my make file:

CFLAGS=-ansi -Wall -pedantic
LFLAGS=-std=c99 -lm 
CC=gcc
all:tm
tm:tm.o tm_coins.o tm_options.o tm_stock.o tm_utility.o
    $(CC) $(LFLAGS) tm.o tm_coins.o tm_options.o tm_stock.o tm_utility.o -o tm $(CFLAGS)

tm.o: tm.h tm.c
    $(CC) $(LFLAGS) $(CFLAGS) -c tm.c

tm_coins.o:tm_coins.h tm_coins.c
    $(CC) $(LFLAGS) $(CFLAGS) -c tm_coins.c

tm_options:tm_options.h tm_options.c
    $(CC) $(LFLAGS) $(CFLAGS) -c tm_options.c

tm_stock:tm_stock.h tm_stock.c
    $(CC) $(LFLAGS) $(CFLAGS) -c tm_stock.c

tm_utility:tm_utility.h tm_utility.c
    $(CC) $(LFLAGS) $(CFLAGS) -c tm_utility.c

With above makefile I get below errors. My understanding is that -std=c99 and -lm doesn't work. (look at the first line below. -std=c99 and -lm are not there)

gcc -ansi -Wall -pedantic   -c -o tm_options.o tm_options.c
tm_options.c: In function ‘purchase_ticket’:
tm_options.c:37: error: expected expression before ‘/’ token
tm_options.c:52: error: expected expression before ‘/’ token
tm_options.c:102: warning: ISO C90 forbids mixed declarations and code
tm_options.c: In function ‘display_tickets’:
tm_options.c:239: error: expected expression before ‘/’ token
tm_options.c: In function ‘add_ticket’:
tm_options.c:285: error: expected expression before ‘/’ token
tm_options.c:303: error: expected expression before ‘/’ token
tm_options.c:314: warning: ISO C90 forbids mixed declarations and code
tm_options.c: In function ‘delete_ticket’:
tm_options.c:387: error: expected expression before ‘/’ token
tm_options.c:405: error: expected expression before ‘/’ token
tm_options.c: In function ‘display_coins’:
tm_options.c:461: error: expected expression before ‘/’ token
tm_options.c: In function ‘restock_tickets’:
tm_options.c:501: error: expected expression before ‘/’ token
tm_options.c: In function ‘restock_coins’:
tm_options.c:526: error: expected expression before ‘/’ token
tm_options.c: In function ‘save_data’:
tm_options.c:555: warning: ISO C90 forbids mixed declarations and code

Where would be the error? Thanks in advance.

Answer 1

For the following three rules, you have forgotten the .o suffix on your targets:

tm_options:tm_options.h tm_options.c
    $(CC) $(LFLAGS) $(CFLAGS) -c tm_options.c

tm_stock:tm_stock.h tm_stock.c
    $(CC) $(LFLAGS) $(CFLAGS) -c tm_stock.c

tm_utility:tm_utility.h tm_utility.c
    $(CC) $(LFLAGS) $(CFLAGS) -c tm_utility.c

This is why the rules you have written do not apply. Instead, it falls back to the default rule for compiling .c sources into .o .

You meant to include it, like so:

tm_options.o:tm_options.h tm_options.c
    $(CC) $(LFLAGS) $(CFLAGS) -c tm_options.c

tm_stock.o:tm_stock.h tm_stock.c
    $(CC) $(LFLAGS) $(CFLAGS) -c tm_stock.c

tm_utility.o:tm_utility.h tm_utility.c
    $(CC) $(LFLAGS) $(CFLAGS) -c tm_utility.c

---

I recommend refactoring your makefile, so you have a generic rule for compiling .c to .o :

%.o: %.c
    $(CC) $(CFLAGS) -o %@ -c %<

Then, you only need to specify the dependencies for your files:

tm_options.o: tm_options.h tm_options.c
tm_stock.o: tm_stock.h tm_stock.c
tm_utility.o: tm_utility.h tm_utility.c

and the above rule is applied automatically. Refactoring your makefile to this will make it easier to spot errors :)

Answer 2

You don't want LFLAGS in the compile commands anyway - put -std=c99 in CFLAGS - the makefile should be more like this:

CFLAGS = -ansi -Wall -pedantic -std=c99
LFLAGS = -lm 
CC = gcc

all: tm

tm: tm.o tm_coins.o tm_options.o tm_stock.o tm_utility.o
    $(CC) $(LFLAGS) tm.o tm_coins.o tm_options.o tm_stock.o tm_utility.o -o tm

tm.o: tm.h tm.c
    $(CC) $(CFLAGS) -c tm.c

tm_coins.o: tm_coins.h tm_coins.c
    $(CC) $(CFLAGS) -c tm_coins.c

tm_options.o: tm_options.h tm_options.c
    $(CC) $(CFLAGS) -c tm_options.c

tm_stock.o: tm_stock.h tm_stock.c
    $(CC) $(CFLAGS) -c tm_stock.c

tm_utility.o: tm_utility.h tm_utility.c
    $(CC) $(CFLAGS) -c tm_utility.c

(I've also added the missing .o suffixes as pointed out by Magnus.)