static Method And Thread Safety
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Hi guys, I am facing a problem regarding static methods, what happens when we call a static method (accessing only local variables), public static void HelpMePlease() { int a=0; a++; Console.WriteLine("A must be 1 " + " a :" + a.ToString()); a++; Console.WriteLine("A must be 2 " + " a :" + a.ToString()); a++; Console.WriteLine("A must be 3 " + " a :" + a.ToString()); a++; Console.WriteLine("A must be 4 " + " a :" + a.ToString()); } Lets suppose, I call this method from 50 threads simultaneously. will All methods keep single copy of a. or each one will have its own copy. Please explain it comprehensively, compiler internals etc. Thanks in advance M.Waseem
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Hi guys, I am facing a problem regarding static methods, what happens when we call a static method (accessing only local variables), public static void HelpMePlease() { int a=0; a++; Console.WriteLine("A must be 1 " + " a :" + a.ToString()); a++; Console.WriteLine("A must be 2 " + " a :" + a.ToString()); a++; Console.WriteLine("A must be 3 " + " a :" + a.ToString()); a++; Console.WriteLine("A must be 4 " + " a :" + a.ToString()); } Lets suppose, I call this method from 50 threads simultaneously. will All methods keep single copy of a. or each one will have its own copy. Please explain it comprehensively, compiler internals etc. Thanks in advance M.Waseem
M.Waseem Chishti wrote: Lets suppose, I call this method from 50 threads simultaneously. will All methods keep single copy of a. or each one will have its own copy. You already wrote the code, what does it do? On the latter part, local variables are created and placed on the stack, so each call will have its own locals. xacc-ide 0.0.15 now with C#, MSIL, C, XML, ASP.NET, Nemerle, MyXaml and HLSL coloring - Screenshots
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Hi guys, I am facing a problem regarding static methods, what happens when we call a static method (accessing only local variables), public static void HelpMePlease() { int a=0; a++; Console.WriteLine("A must be 1 " + " a :" + a.ToString()); a++; Console.WriteLine("A must be 2 " + " a :" + a.ToString()); a++; Console.WriteLine("A must be 3 " + " a :" + a.ToString()); a++; Console.WriteLine("A must be 4 " + " a :" + a.ToString()); } Lets suppose, I call this method from 50 threads simultaneously. will All methods keep single copy of a. or each one will have its own copy. Please explain it comprehensively, compiler internals etc. Thanks in advance M.Waseem
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Hi guys, I am facing a problem regarding static methods, what happens when we call a static method (accessing only local variables), public static void HelpMePlease() { int a=0; a++; Console.WriteLine("A must be 1 " + " a :" + a.ToString()); a++; Console.WriteLine("A must be 2 " + " a :" + a.ToString()); a++; Console.WriteLine("A must be 3 " + " a :" + a.ToString()); a++; Console.WriteLine("A must be 4 " + " a :" + a.ToString()); } Lets suppose, I call this method from 50 threads simultaneously. will All methods keep single copy of a. or each one will have its own copy. Please explain it comprehensively, compiler internals etc. Thanks in advance M.Waseem
Here is how the IL code looks like:
.method public hidebysig static void HelpMePlease() cil managed
{
// Code Size: 107 byte(s)
.maxstack 2
.locals (
int32 num1)
L_0000: ldc.i4.0
L_0001: stloc.0
L_0002: ldloc.0
L_0003: ldc.i4.1
L_0004: add
L_0005: stloc.0
L_0006: ldstr "A must be 1 a :"
L_000b: ldloca.s num1
L_000d: call instance string int32::ToString()
L_0012: call string string::Concat(string, string)
L_0017: call void [mscorlib]System.Console::WriteLine(string)
L_001c: ldloc.0
L_001d: ldc.i4.1
L_001e: add
L_001f: stloc.0
L_0020: ldstr "A must be 2 a :"
L_0025: ldloca.s num1
L_0027: call instance string int32::ToString()
L_002c: call string string::Concat(string, string)
L_0031: call void [mscorlib]System.Console::WriteLine(string)
L_0036: ldloc.0
L_0037: ldc.i4.1
L_0038: add
L_0039: stloc.0
L_003a: ldstr "A must be 3 a :"
L_003f: ldloca.s num1
L_0041: call instance string int32::ToString()
L_0046: call string string::Concat(string, string)
L_004b: call void [mscorlib]System.Console::WriteLine(string)
L_0050: ldloc.0
L_0051: ldc.i4.1
L_0052: add
L_0053: stloc.0
L_0054: ldstr "A must be 4 a :"
L_0059: ldloca.s num1
L_005b: call instance string int32::ToString()
L_0060: call string string::Concat(string, string)
L_0065: call void [mscorlib]System.Console::WriteLine(string)
L_006a: ret
}.maxstack 2-- this allocates space for your variable on the stack. As the local variables are allocated on the stack, every call to the method has it's own set of variables. Your function is thread safe. (As the Console class is also thread safe, even the writing to the console is thread safe. It might look awful if you have several threads writing to it at the same time, but it's safe.) --- b { font-weight: normal; } -
M.Waseem Chishti wrote: Lets suppose, I call this method from 50 threads simultaneously. will All methods keep single copy of a. or each one will have its own copy. You already wrote the code, what does it do? On the latter part, local variables are created and placed on the stack, so each call will have its own locals. xacc-ide 0.0.15 now with C#, MSIL, C, XML, ASP.NET, Nemerle, MyXaml and HLSL coloring - Screenshots
yeah all methods are maintaining their own copies. all i wanted to know is what copiler does when a method is called ?? is there any diffrence between behaviour of compiler when you call a static method ??
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Hello... In other words: 1. Every Thread contains his own stack... 2. Local variables are always stored on the stack from the specified thread (each one have its own copy)... --> The static keyword before functions haves no effect on there locals... :)
Thankx :-D
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Here is how the IL code looks like:
.method public hidebysig static void HelpMePlease() cil managed
{
// Code Size: 107 byte(s)
.maxstack 2
.locals (
int32 num1)
L_0000: ldc.i4.0
L_0001: stloc.0
L_0002: ldloc.0
L_0003: ldc.i4.1
L_0004: add
L_0005: stloc.0
L_0006: ldstr "A must be 1 a :"
L_000b: ldloca.s num1
L_000d: call instance string int32::ToString()
L_0012: call string string::Concat(string, string)
L_0017: call void [mscorlib]System.Console::WriteLine(string)
L_001c: ldloc.0
L_001d: ldc.i4.1
L_001e: add
L_001f: stloc.0
L_0020: ldstr "A must be 2 a :"
L_0025: ldloca.s num1
L_0027: call instance string int32::ToString()
L_002c: call string string::Concat(string, string)
L_0031: call void [mscorlib]System.Console::WriteLine(string)
L_0036: ldloc.0
L_0037: ldc.i4.1
L_0038: add
L_0039: stloc.0
L_003a: ldstr "A must be 3 a :"
L_003f: ldloca.s num1
L_0041: call instance string int32::ToString()
L_0046: call string string::Concat(string, string)
L_004b: call void [mscorlib]System.Console::WriteLine(string)
L_0050: ldloc.0
L_0051: ldc.i4.1
L_0052: add
L_0053: stloc.0
L_0054: ldstr "A must be 4 a :"
L_0059: ldloca.s num1
L_005b: call instance string int32::ToString()
L_0060: call string string::Concat(string, string)
L_0065: call void [mscorlib]System.Console::WriteLine(string)
L_006a: ret
}.maxstack 2-- this allocates space for your variable on the stack. As the local variables are allocated on the stack, every call to the method has it's own set of variables. Your function is thread safe. (As the Console class is also thread safe, even the writing to the console is thread safe. It might look awful if you have several threads writing to it at the same time, but it's safe.) --- b { font-weight: normal; }is there no diffrence between how compiler treats a static method and an instance method (if both are only accessing their local variables) ??
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yeah all methods are maintaining their own copies. all i wanted to know is what copiler does when a method is called ?? is there any diffrence between behaviour of compiler when you call a static method ??
When you call a static method, there is no reference to the object, as there is no object. Other than that, there is no difference. Calling a static method does not use the address of an object:
Console.WriteLine("test");
ldstr "test"
call void [mscorlib]System.Console::WriteLine(string)Calling a non-static method uses the address of the object:
num.ToString("d4");
ldloca.s num
ldstr "d4"
call instance string int32::ToString()--- b { font-weight: normal; }
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is there no diffrence between how compiler treats a static method and an instance method (if both are only accessing their local variables) ??