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POhow to run same jar file multiple times by forking new child process every time?
 

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  1. POhow to run same jar file multiple times by forking new child process every time?
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    <p>i am trying to write a c++ program. the program is required to run some jar files, run every jar file two times. the problem is that the program runs every file just one time correctly. at the second time i got an error message, as if the VM got a wrong command. However, it is the same command that run the jar files the first time !!!</p> <p>This is the first few lines of the red-colored error message that i got.</p> <pre><code>Usage: java [-options] class [args...] (to execute a class) or java [-options] -jar jarfile [args...] (to execute a jar file) where options include: -d32 use a 32-bit data model if available -d64 use a 64-bit data model if available -client to select the "client" VM -server to select the "server" VM </code></pre> <p>This is my code. This is the main file:</p> <pre><code>#include &lt;iostream&gt; #include &lt;fstream&gt; #include &lt;signal.h&gt; #include &lt;string.h&gt; #include &lt;time.h&gt; #include "StringParser.h" #include "ShellCore.h" using namespace std; int main() { while (1) { char checkers_command[] = "java -jar /home/samer/Downloads/chkr.jar"; char castle_command[] = "java -jar /home/samer/Downloads/cas.jar"; int child_status; bool wait_bool = true; cout &lt;&lt; "Run Batch Shell&gt; "; cin.getline(input_command_line, 256); if (strcasecmp("exit", input_command_line) == 0) { cout &lt;&lt; "The shell program will terminate\n"; exit(0); } else { char* commands; for (int var = 0; var &lt; 4; ++var) { if (var % 2 == 0) { commands = checkers_command; } else if (var % 2 == 1) { commands = castle_command; } char* arg_list_tokened[50]; parse_command_line(arg_list_tokened, commands); spawn(arg_list_tokened[0], arg_list_tokened); if (wait_bool) { // The parent wait until the child finishes. cout &lt;&lt; "The parent will wait for " &lt;&lt; arg_list_tokened[0] &lt;&lt; endl; wait(&amp;child_status); if (WIFEXITED(child_status)) { printf("The child process exited normally with exit code %d\n", WEXITSTATUS(child_status)); } else { printf("The child process exited abnormally\n"); } } } cout &lt;&lt; "done\n"; } } return 0; } </code></pre> <p>This is the "spawn" method in the Shellcore.cpp file: The Shellcore.h contains the required includes for the Shellcore.cpp.</p> <pre><code>#include "ShellCore.h" pid_t child_pid; int spawn(char* program_name, char** args) { child_pid = fork(); if (child_pid != 0) { return child_pid; } else { execvp(program_name, args); // If the execvp return, this indicate that an error occurred. printf("From the spawn function in the parent process, execvp ERROR\n"); abort(); } } </code></pre> <p>sorry for the long question and long code. Thanks is advance :)</p> <p>The parse function:</p> <pre><code>void parse_command_line(char* output_list[], char* command_line) { char * pch; int i = 0; pch = strtok(command_line, " &amp;\""); output_list[0] = pch; while (pch != NULL) { i++; pch = strtok(NULL, " &amp;\""); output_list[i] = pch; } output_list[++i] = NULL; } </code></pre>
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    1. USSeki
    1. USSamer Makary
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      1. POhow to run same jar file multiple times by forking new child process every time?
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      1. VTUpMod
    2. VO
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    1. COI think the problem is in parse_command_line, or your use of it. Can you paste the source code for that function?
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      1. POhow to run same jar file multiple times by forking new child process every time?
      1. USRobin Green
    2. COi don think so as the parse function works for the first time with every jar file.
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      1. POhow to run same jar file multiple times by forking new child process every time?
      1. USSamer Makary
    3. COYeah what I'm suggesting is that it doesn't work the second time! C++ is not Haskell - functions don't necessarily do the same thing every time like they do in Haskell!
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      1. POhow to run same jar file multiple times by forking new child process every time?
      1. USRobin Green
 

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