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Difference between revisions of "cpp/numeric/fenv/feenv"

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< cpp‎ | numeric‎ | fenv
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{{cpp/title|fegetenv|fesetenv}}
 
{{cpp/title|fegetenv|fesetenv}}
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{{cpp/numeric/fenv/sidebar}}
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{{cpp/numeric/fenv/navbar}}
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{{ddcl list begin}}
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{{dcl begin}}
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{{ddcl list header | cfenv}}
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{{dcl header | cfenv}}
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{{ddcl list item | notes={{mark since c++11}} | num=1|
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{{dcl | since=c++11 | num=1|
 
int fegetenv( std::fenv_t* envp )
 
int fegetenv( std::fenv_t* envp )
 
}}
 
}}
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{{ddcl list item | notes={{mark since c++11}} | num=2|
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{{dcl | since=c++11 | num=2|
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int fesetenv(const std::fenv_t* envp);
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int fesetenv( const std::fenv_t* envp );
 
}}
 
}}
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{{ddcl list end}}
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{{dcl end}}
  
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1) Attempts to store the status of the floating-point environment in the object pointed to by {{tt|envp}}.
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Manages the status of the floating-point environment.
  
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2) Attempts to establish the floating-point environment from the object pointed to by {{tt|envp}}. The value of that object must be previously obtained by a call to {{cpp|std::feholdexcept}} or {{tt|std::fegetenv}} or be a floating-point macro constant. If any of the floating-point status flags are set in {{tt|envp}}, they become set in the environment (and are then testable with {{cpp|std::fetestexcept}}), but the corresponding floating-point exceptions are not raised (execution continues uninterrupted)
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@1@ Attempts to store the status of the floating-point environment in the object pointed to by {{tt|envp}}.
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@2@ Attempts to establish the floating-point environment from the object pointed to by {{tt|envp}}. The value of that object must be previously obtained by a call to {{lc|std::feholdexcept}} or {{tt|std::fegetenv}} or be a floating-point macro constant. If any of the floating-point status flags are set in {{tt|envp}}, they become set in the environment (and are then testable with {{lc|std::fetestexcept}}), but the corresponding floating-point exceptions are not raised (execution continues uninterrupted)
  
 
===Parameters===
 
===Parameters===
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{{param list begin}}
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{{par begin}}
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{{param list item | envp | pointer to the object of type {{cpp|std::fenv_t}} which holds the status of the floating-point environment}}
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{{par | envp | pointer to the object of type {{c|std::fenv_t}} which holds the status of the floating-point environment}}
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{{param list end}}
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{{par end}}
  
 
===Return value===
 
===Return value===
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{{cpp|0}} on success, non-zero otherwise.
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{{c|0}} on success, non-zero otherwise.
  
 
===See also===
 
===See also===
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{{dcl list begin}}
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{{dsc begin}}
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{{dcl list template | cpp/numeric/fenv/dcl list feholdexcept}}
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{{dsc inc | cpp/numeric/fenv/dsc feholdexcept}}
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{{dcl list template | cpp/numeric/fenv/dcl list feupdateenv}}
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{{dsc inc | cpp/numeric/fenv/dsc feupdateenv}}
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{{dcl list template | cpp/numeric/fenv/dcl list FE_DFL_ENV}}
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{{dsc inc | cpp/numeric/fenv/dsc FE_DFL_ENV}}
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{{dcl list end}}
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{{dsc see c | c/numeric/fenv/feenv | fegetenv | fesetenv}}
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{{dsc end}}
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{{langlinks|de|es|fr|it|ja|pt|ru|zh}}

Latest revision as of 07:45, 18 September 2017

 
C++
 
Numerics library
Common mathematical functions
Mathematical special functions (C++17)
Mathematical constants (C++20)
Basic linear algebra algorithms (C++26)
Floating-point environment (C++11)
Complex numbers
Numeric array (valarray)
Pseudo-random number generation
Factor operations
(C++17)
(C++17)
Interpolations
(C++20)
(C++20)
Saturation arithmetic
(C++26)
(C++26)
(C++26)
(C++26)
(C++26)

Generic numeric operations
Bit operations
(C++20)    
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++23)
(C++20)
 
Floating-point environment
Functions
(C++11)
(C++11)
(C++11)
(C++11)(C++11)
(C++11)(C++11)
fegetenvfesetenv
(C++11)(C++11)
(C++11)
(C++11)
Macro constants
(C++11)(C++11)(C++11)(C++11)(C++11)(C++11)
(C++11)(C++11)(C++11)(C++11)
(C++11)
 
Defined in header <cfenv>
int fegetenv( std::fenv_t* envp )
 (1) (since C++11)
int fesetenv( const std::fenv_t* envp );
 (2) (since C++11)

Manages the status of the floating-point environment.

1) Attempts to store the status of the floating-point environment in the object pointed to by envp.
2) Attempts to establish the floating-point environment from the object pointed to by envp. The value of that object must be previously obtained by a call to std::feholdexcept or std::fegetenv or be a floating-point macro constant. If any of the floating-point status flags are set in envp, they become set in the environment (and are then testable with std::fetestexcept), but the corresponding floating-point exceptions are not raised (execution continues uninterrupted)

[edit] Parameters

envp - pointer to the object of type std::fenv_t which holds the status of the floating-point environment

[edit] Return value

​0​ on success, non-zero otherwise.

[edit] See also

(C++11)
 saves the environment, clears all status flags and ignores all future errors
(function) [edit]
(C++11)
 restores the floating-point environment and raises the previously raised exceptions
(function) [edit]
(C++11)
 default floating-point environment
(macro constant) [edit]
C documentation for fegetenv, fesetenv
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