How to put variable as argument in system()

Question

I am trying to include the sleep 1 command in bash in my .cpp file
While system("sleep 1") works fine, I would like to change 1 into a const int or string

const string t = "1";
string c = "sleep " + t;
system(c);

However, it seems like the system(c) is treated as a call to function as the following error occurs:

error: no matching function for call to 'system'
  system(c);

How can I resolve this?

Does calling it as "system(c.c_str());" help? – Joseph Larson Mar 12 '21 at 16:34 — Joseph Larson, Mar 12 '21 at 16:34
`system(c)` is a call to a function – 463035818_is_not_an_ai Mar 12 '21 at 16:36 — 463035818_is_not_an_ai, Mar 12 '21 at 16:36
@JosephLarson Yes it is solved, thank you. – appleline Mar 12 '21 at 16:46 — appleline, Mar 12 '21 at 16:46

score 4 · Accepted Answer · edited Mar 14 '21 at 15:14

4

The system function takes a const char* pointer as its argument. However, there is no implicit conversion from a std::string object to a const char* (representing its contained string data) provided by the Standard Library. Instead, you can call the c_str() member function on that object, like so:

system(c.c_str());

edited Mar 14 '21 at 15:14

dreamcrash

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answered Mar 12 '21 at 16:37

Adrian Mole

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score 3 · Answer 2 · answered Mar 12 '21 at 16:35

3

system(c.c_str()) or, equivalently (from C++11), system(c.data())

answered Mar 12 '21 at 16:35

user2052436

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How to put variable as argument in system()

2 Answers2