command line prompt command (want to understand what its doing)

Question

I am doing the CS50 class, I have installed the cs50.h. Based on the instructions I used the following command in terminal to compile my simple program and just want to make sure I understand everything im asking terminal to do. Line is:

gcc -g hello.c -o hello -lcs50 -lm

I know the following*: gcc =

gcc = gnu compiler for C
-g = generate source-level debug information
Hello.c = name of the file we want to compile
-o = write output file
hello = our output file name

Can anyone tell me what -lcs50 and -lm are? My guess is that its calling on the library lcs50 in (-lcs50) but again this is a guess and would like to know for sure.

Everything works as it should with no issues

Thanks,

score 0 · Answer 1 · answered Jul 03 '22 at 18:08

0

Yes. For -lm, it's for the maths library, which is not linked by default. This is explained well at Why do you need an explicit `-lm` compiler option.

answered Jul 03 '22 at 18:08

Leaderboard

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Thank you! So then is my assumption right that -lcs50 is just the library I am calling on so that #include works in my code? – slipperfox Jul 03 '22 at 18:11
Yes (assuming that I've understood the purpose of ``cs50.h`` correctly). – Leaderboard Jul 03 '22 at 18:12

score 0 · Accepted Answer · answered Jul 03 '22 at 18:26

Mostly correct.

-o is not required to generate the output file, it's only needed to customize the name. (-o and the following name can only appear together).
-lcs50 means "link the library called cs50", not lcs50. It will try to find this file using several different name patterns, e.g. libcs50.so (on Linux), [lib]cs50.dll[.a] (on Windows), libcs50.a (on both), something else on Mac.
-lm links the standard math library, but I don't think you need to manually specify it on most modern GCC distributions.

command line prompt command (want to understand what its doing)

2 Answers2