R: Evaluate a C++ Expression

evalCpp {Rcpp} | R Documentation

## Evaluate a C++ Expression

### Description

Evaluates a C++ expression. This creates a C++ function using `cppFunction` and calls it to get the result.

### Usage

    evalCpp(code, depends = character(), plugins = character(), includes = character(),
            rebuild = FALSE, cacheDir = getOption("rcpp.cache.dir", tempdir()),
            showOutput = verbose, verbose = getOption("verbose"))

    areMacrosDefined(names, depends = character(), includes = character(),
            rebuild = FALSE, showOutput = verbose,
            verbose = getOption("verbose"))

### Arguments

`code` | C++ expression to evaluate
`names` | names of the macros we want to test
`plugins` | see `cppFunction`
`depends` | see `cppFunction`
`includes` | see `cppFunction`
`rebuild` | see `cppFunction`
`cacheDir` | Directory to use for caching shared libraries. If the underlying code passed to `sourceCpp` has not changed since the last invocation then a cached version of the shared library is used. The default value of `tempdir()` results in the cache being valid only for the current R session. Pass an alternate directory to preserve the cache across R sessions.
`showOutput` | see `cppFunction`
`verbose` | see `cppFunction`

### Value

The result of the evaluated C++ expression.

### Note

The result type of the C++ expression must be compatible with `Rcpp::wrap`.

### See Also

`sourceCpp`, `cppFunction`

### Examples

    ## Not run:

    evalCpp( "__cplusplus" )
    evalCpp( "std::numeric_limits<double>::max()" )

    areMacrosDefined( c("__cplusplus", "HAS_TR1" ) )

    ## End(Not run)

[Package Rcpp version 1.0.8 Index]