GCC笔记

#10

gcc -DTEST #define TEST, if source code include "ifdef TEST" there are a lot of ...

cpp -dM /dev/null

gcc -DName=Value test.c #Name is not need to be defined in source code.

gcc -E test.c #No compile,just see the predefine process result

#11

gcc -g test.c #option for debugging, recommended for development and deployment

ulimit -c unlimited #for creating core-dump file

gdb a.out core-file #gdb need two file(source+dump)

#12

#Function call overhead (额外开销)

#13

gcc -O0 test.c #no optimization, 03 is highest level.

time ./a.out #output the executed time

gcc -O2 test.c #Data-flow analysis, for instance,no initialized variable will be warning

#14

gcc

g++

#15

cpp test.c > test.i #C PreProcess

gcc -S test.i # to assembly language named test.s

as test.s -o test.o

file a.out #inform for a file

nm #symbol table

ldd #load dynamic libarary

#16

gcc -Wall -pg test.c #gprof 

gprof a.out #gmon.out

gcc -Wall -fprofile-arcs -ftest-coverage test.c #gcov

grep "#####" test.gconv #display the uncovered lines